Ingest data with Node.js on Elasticsearch Service

This guide tells you how to get started with:

If you are an Node.js application programmer who is new to the Elastic Stack, this content helps you get started more easily.

Time required: 45 minutes

Prefer not to subscribe to yet another service? You can also get Elasticsearch Service through AWS, Azure, and GCP marketplaces.

These steps are applicable to your existing application. If you don’t have one, use the example included here to create one.

npm init

npm install @elastic/elasticsearch
npm install config

mkdir config
vi config/default.json

The example here shows what the config package expects. You need to update config/default.json with your deployment details in the following sections:

{
  "elastic": {
    "cloudID": "DEPLOYMENT_NAME:CLOUD_ID_DETAILS", 
    "username": "elastic",
    "password": "LONGPASSWORD"
  }
}

When connecting to Elasticsearch Service use a Cloud ID to specify the connection details. You must pass the Cloud ID that is found in Kibana or the cloud console.

To connect to, stream data to, and issue queries with Elasticsearch Service, you need to think about authentication. Two authentication mechanisms are supported, API key and basic authentication. Here, to get you started quickly, we’ll show you how to use basic authentication, but you can also generate API keys as shown later on. API keys are safer and preferred for production environments.

For basic authentication, use the same deployment credentials (username and password parameters) and Cloud ID you copied down earlier when you created your deployment. (If you did not save the password, you can reset the password .)

The sample application connects to Elasticsearch, creates an index, inserts some records, performs a search, and updates a record.

Read the configuration created earlier, and connect to Elasticsearch:

const { Client } = require('@elastic/elasticsearch')
const config = require('config');
const elasticConfig = config.get('elastic');

const client = new Client({
  cloud: {
    id: elasticConfig.cloudID
  },
  auth: {
    username: elasticConfig.username,
    password: elasticConfig.password
  }
})

Now confirm that you are connected to the deployment by returning some information about the deployment:

client.info()
  .then(response => console.log(response))
  .catch(error => console.error(error))

After connecting to your deployment, you are ready to index and search data. Let’s create a new index, insert some quotes from our favorite characters, and refresh the index so that it is ready to be searched. A refresh makes all operations performed on an index since the last refresh available for search.

async function run() {
  await client.index({
    index: 'game-of-thrones',
    body: {
      character: 'Ned Stark',
    quote: 'Winter is coming.'
    }
  })

  await client.index({
    index: 'game-of-thrones',
    body: {
      character: 'Daenerys Targaryen',
    quote: 'I am the blood of the dragon.'
    }
  })

  await client.index({
    index: 'game-of-thrones',
    body: {
      character: 'Tyrion Lannister',
    quote: 'A mind needs books like a sword needs whetstone.'
    }
  })

  await client.indices.refresh({index: 'game-of-thrones'})
}

run().catch(console.log)

When using the client.index API, the request automatically creates the game-of-thrones index if it doesn’t already exist, as well as document IDs for each indexed document if they are not explicitly specified.

After creating a new index and ingesting some data, you are now ready to search. Let’s find what characters have said things about winter:

async function read() {
  const { body } = await client.search({
    index: 'game-of-thrones',
    body: {
      query: {
        match: { quote: 'winter' }
      }
    }
  })
  console.log(body.hits.hits)
}

read().catch(console.log)

The search request returns content of documents containing 'winter' in the quote field, including document IDs that were automatically generated. You can make updates to specific documents using document IDs. Let’s add a birthplace for our character:

async function update() {
  await client.update({
    index: 'game-of-thrones',
    id: <ID>,
    body: {
      script: {
        source: "ctx._source.birthplace = 'Winterfell'"
      }
    }
  })
  const { body } = await client.get({
    index: 'game-of-thrones',
    id: <ID>
  })

  console.log(body)
}

update().catch(console.log)

This more comprehensive list of API examples includes bulk operations, checking the existence of documents, updating by query, deleting, scrolling, and SQL queries. To learn more, check the complete API reference.

To get started, authentication to Elasticsearch used the elastic superuser and password, but an API key is much safer and a best practice for production.

In the example that follows, an API key is created with the cluster monitor privilege which gives read-only access for determining the cluster state. Some additional privileges also allow create_index, write, read, and manage operations for the specified index. The index manage privilege is added to enable index refreshes.

The security.createApiKey function returns an id and api_key value which can then be concatenated and encoded in base64:

async function generateApiKeys (opts) {
  const { body } = await client.security.createApiKey({
    body: {
      name: 'nodejs_example',
      role_descriptors: {
        'nodejs_example_writer': {
          'cluster': ['monitor'],
          'index': [
            {
              'names': ['game-of-thrones'],
              'privileges': ['create_index', 'write', 'read', 'manage']
            }
          ]
        }
      }
    }
  })

  return Buffer.from(`${body.id}:${body.api_key}`).toString('base64')
}

generateApiKeys()
  .then(console.log)
  .catch(err => {
  console.error(err)
  process.exit(1)
})

The base64 encoded output is as follows and is ready to be added to the configuration file:

API_KEY_DETAILS

Edit the config/default.json configuration file you created earlier and add this API key:

{
  "elastic-cloud": {
    "cloudID": "DEPLOYMENT_NAME:CLOUD_ID_DETAILS",
    "username": "elastic",
    "password": "LONGPASSWORD",
    "apiKey": "API_KEY_DETAILS"
  }
}

Now the API key can be used in place of the username and password. The client connection becomes:

const elasticConfig = config.get('elastic-cloud');

const client = new Client({
  cloud: {
    id: elasticConfig.cloudID
  },
  auth: {
    apiKey: elasticConfig.apiKey
  }
})

Check Create API key API to learn more about API Keys and Security privileges to understand which privileges are needed. If you are not sure what the right combination of privileges for your custom application is, you can enable audit logging on Elasticsearch to find out what privileges are being used. To learn more about how logging works on Elasticsearch Service, check Monitoring Elastic Cloud deployment logs and metrics.